Signal processor in multiplex communication system utilizing a changeover signal indicating a change in gain of the transmission signal and the signal processing method for the system

ABSTRACT

A signal generating unit is arranged to generate a filter changeover signal a, which indicates the changeover from a plurality of waveform reshaping units of a first group corresponding to the reception of the modulated signals to a plurality of waveform reshaping units of a second group, in cases where an electric power gain value of the transmission signal is changed, to send the changeover signal a to the filter selecting unit, to generate a new gain signal of which a new electric power gain value is changed from an electric power gain value of the gain signal to send the new gain signal to the multipliers corresponding to the waveform reshaping units of the second group, and to successively send the gain signal having the electric power gain value to the multipliers corresponding to the waveform reshaping units of the first group during a prescribed time period after the change of the gain signal to the new gain signal.

This application is the national phase under 35 U.S.C. § 371 of PCTInternational Application No. PCT/JP00/02046 which has an Internationalfiling date of Mar. 30, 2000, which designated the United States ofAmerica and was not published in English.

TECHNICAL FIELD

The present invention relates to a signal processing device in amultiplex communication system, in which pieces of information aretransmitted in a plurality of channels respectively, and a signalprocessing method performed in the system.

BACKGROUND ART

In a conventional signal processing device in a multiplex communicationsystem, pieces of information are transmitted through a sharedtransmission path or space in a plurality of channels respectively. Asan example of this type of multiplex communication system, communicationsystems based on frequency division multiple access (FDMA), timedivision multiple access (TDMA) and code division multiple access (CDMA)are known.

In particular, in case of the CDMA communication system, a plurality ofusers can share a frequency band. Therefore, as compared with the FDMAcommunication system and the TDMA communication system, the number ofchannels per a certain bandwidth can be increased. Also, because signalsof a broad-band frequency are transmitted in the CDMA communicationsystem, adverse influence of frequency selective fading due tomulti-path signals is low. Therefore, it is expected that the CDMAcommunication system is useful for mobile communication.

In a CDMA communication system applied for the mobile communication, twopieces of information different from each other are, for example,transmitted from a mobile station in two channels respectively. Forexample, Published Unexamined Japanese Patent Application H11-266168 waslaid open to public inspection on Sep. 28, 1999. In this patentapplication, method and device of adjusting an electric power of eachtransmission signal in the simultaneous transmission of both an audiosignal and a data signal is disclosed.

FIG. 1 is a block diagram showing the configuration of a conventionalsignal processing device (or a base-band modulating device) in the CDMAcommunication system. In FIG. 1, 31 indicates a spreading modulatingunit for performing a direct spreading modulation for two input signalsof two channels CH1 and CH2 as a spreading modulation according to twopseudo noise signals input from Code 1 and Code 2. The spreadingmodulating unit 31 is composed of four exclusive OR gates 31 a, 31 b, 31c and 31 d.

32 to 35 indicate waveform reshaping units for limiting four modulatedsignals sent from the spreading modulating unit 31. 36 to 39 indicatechannel gain multipliers (hereinafter, called multipliers) forrespectively multiplying a reshaped modulated signal sent from one ofthe waveform reshaping units 32 to 35 by a gain of a gain signal foreach channel. 40 indicates an adder for adding together signals sentfrom the multipliers 36 and 37. 41 indicates an adder for addingtogether signals sent from the multipliers 38 and 39.

Next, an operation of the conventional signal processing device shown inFIG. 1 will be described below. Two types of signals (for example, anaudio signal and a data signal) of two transmission channels CH1 and CH2are received in the spreading modulating unit 31. The signal of thechannel CH1 is received in the exclusive OR gates 31 a and 31 c, and thesignal of the channel CH2 is received in the exclusive OR gates 31 b and31 d.

Also, a pseudo noise signal of the Code 1 is received in the exclusiveOR gates 31 a and 31 d, and a pseudo noise signal of the Code 2 isreceived in the exclusive OR gates 31 b and 31 c.

Therefore, the modulation of quadrature phase shift keying (QPSK) isperformed for the two types of signals of the transmission channels CH1and CH2 in the exclusive OR gates 31 a to 31 d, and a frequency band ofeach signal is spread to a spread frequency band which is tens times ofthe frequency band. In this case, the signals of the channels CH1 andCH2 are modulated in the exclusive OR gates 31 a to 31 d to produce twomodulated signals I_(CH1) and I_(CH2) of an I component and twomodulated signals Q_(CH1) and Q_(CH2) of a Q component according tofollowing multiplication equations.I _(CH1) =CH 1×Code 1I _(CH2) =−CH 2×Code 2Q _(CH1) =CH 1×Code 2Q _(CH2) =CH 2×Code 1

The modulated signals I_(CH1), I_(CH2), Q_(CH1) and Q_(CH2) areorthogonal to each other. The modulated signals I_(CH1), I_(CH2),Q_(CH1) and Q_(CH2) spread in the exclusive OR gates 31 a to 31 d areinput to the waveform reshaping units 32 to 35 respectively.

In the waveform reshaping units 32 to 35, waveforms of the modulatedsignals I_(CH1), I_(CH2), Q_(CH1) and Q_(CH2) are reshaped. In detail,an impulse response is superposed on each of the modulated signalsI_(CH1), I_(CH2), Q_(CH1) and Q_(CH2) to limit the waveband of eachmodulated signal, and reshaped modulated signals I′_(CH1), I′_(CH2),Q′_(CH1) and Q′_(CH2) are produced and input to the multipliers 36, 37,38 and 39.

In each of the multipliers 36, 37, 38 and 39, the reshaped modulatedsignal I′_(CH1), I′_(CH2), Q′_(CH1) and Q′_(CH2) is multiplied by achannel gain (or an electric power gain value) βd, βc, βd or βc of again signal sent from a signal generating unit (not shown) to produce anelectric power controlled modulation signal I′_(CH1)*βd, I′_(CH2)*βc,Q′_(CH1)*βd or Q′_(CH2)* βc.

Thereafter, two types of electric power controlled modulation signalsI′_(CH1)*βd and I′_(CH2)*βc are received in the adder 40 and are addedtogether according to a following equation. Therefore, a compositemodulation signal Imod is produced. In the same manner, two types ofelectric power controlled modulation signals Q′_(CH1)*βd and Q′_(CH2)*βcare received in the adder 41 and are added together according to anotherfollowing equation. Therefore, a composite modulation signal Qmod isproduced. That is, the frequency spread modulation signal Imod of the Icomponent and the frequency spread modulation signal Qmod of the Qcomponent are produced.Imode=βd*I′ _(CH1) +βc*I′ _(CH2)Qmode=βd*Q′ _(CH1) +βc*Q′ _(CH2)

These frequency spread modulation signals Imod and Qmode are convertedinto analog signals in digital-to-analog converters (not shown)respectively and are input to high frequency modulating units (notshown) respectively. In each high frequency modulating unit, the analogsignal is modulated with a high frequency carrier signal to produce atransmission signal, and the transmission signal is output as anelectric wave.

In this case, to control an electric power of the transmission signal inthe CDMA communication system, the channel gain is sometimes changedduring the transmission of the signal.

FIG. 2 shows an example of the change of the channel gain βd of thechannel CH1 in the conventional signal processing device shown inFIG. 1. In cases where the channel gain βd is periodically changed toβd1, βd2, βd3, βd4, - - - stepwise at constant time periods withoutchanging the channel gain βc of the channel CH2, an output signal (or anelectric power controlled modulation signal) h′ of the multiplier 36 andan output signal (or an electric power controlled modulation signal) k′of the multiplier 37 have waveforms of h′ and k′ shown in FIG. 2respectively. Therefore, an output signal (or a composite modulationsignal) m′ of the adder 40 has a waveform of m′ shown in FIG. 2, and anelectric power value of the transmission signal is changed stepwise.

However, in the conventional signal processing device of the CDMAcommunication system, the band widths of the signals output from thewaveform reshaping units 32 to 35 are limited, and the impulse responseis superposed on the modulated signal at each sampling point in thewaveform reshaping units 32 to 35. Therefore, there is a transientresponse in each output signal. Therefore, in cases where the channelgain is changed stepwise, the gain is sometimes changed in the middle ofthe impulse response. In this case, distortion occurs in the waveform ofthe transient response, and the bandwidth of the transmission signal isundesirably widened. Therefore, a problem has arisen that the leaking ofan electric power of the transmission signal to a signal of an adjacentfrequency channel is increased.

The present invention is provided to solve the above-described problem,and the object of the present invention is to provide a signalprocessing device and a signal processing method of the CDMAcommunication system in which the leaking of an electric power of atransmission signal to a signal of an adjacent frequency channel issuppressed even though a channel gain for the transmission signal ischanged stepwise.

DISCLOSURE OF THE INVENTION

A signal processing device of a multiplex communication according to thepresent invention comprises waveform reshaping means (waveform reshapingunits) of first and second groups for reshaping waveforms of themodulated signals to produce a plurality of reshaped modulation signals,selecting means (filter selecting unit) for selecting the waveformreshaping means of the first group or the waveform reshaping means ofthe second group according to a changeover signal (filter changeoversignal) and receiving a plurality of modulated signals, multiplyingmeans (channel multipliers) of the first and second groups, whichcorrespond to the waveform reshaping means of the first and secondgroups respectively, for multiplying each reshaped modulation signalproduced by the waveform reshaping means of the corresponding group by again signal for each of the first and second groups to produce aplurality of electric power controlled signals, adding means (channeladders) for adding together the electric power controlled signalsproduced by the multiplying means of the first and second groups toproduce a composite modulation signal corresponding to a transmissionsignal, and signal generating means (channel gain setting unit) forgenerating the changeover signal, which indicates the changeover fromthe waveform reshaping means of the first group corresponding to thereception of the modulated signals to the waveform reshaping means ofthe second group, in cases where an electric power gain value of thetransmission signal is changed, sending the changeover signal to theselecting means, generating a new gain signal of which a new electricpower gain value is changed from an electric power gain value of thegain signal, sending the new gain signal to the multiplying meanscorresponding to the waveform reshaping means of the second group, andsuccessively sending the gain signal having the electric power gainvalue to the multiplying means corresponding to the waveform reshapingmeans of the first group during a prescribed time period after thechange of the gain signal to the new gain signal.

Therefore, even though a channel gain denoting an electric power gainvalue of the transmission signal is changed stepwise, no distortionoccurs in a waveform of a transient response, and a band of thetransmission signal is not widened. Accordingly, an electric power ofthe transmission signal can be prevented from being leaked to a signalof an adjacent frequency channel.

In a signal processing device of a multiplex communication according tothe present invention, the gain signal having the electric power gainvalue is successively sent to the multiplying means corresponding to thewaveform reshaping means of the first group by the signal generatingmeans until a transient response of the waveform reshaping means of thefirst group is completed.

Therefore, even though a channel gain denoting an electric power gainvalue of the transmission signal is changed stepwise, distortion can bereliably prevented from occurring in a waveform of a transient response.Accordingly, a band of the transmission signal is not widened, and anelectric power of the transmission signal can be prevented from beingleaked to a signal of an adjacent frequency channel.

In a signal processing device of a multiplex communication according tothe present invention, the changeover signal indicating the changeoverof the waveform reshaping means is periodically generated by the signalgenerating means and is sent to the selecting means.

Therefore, even though a channel gain denoting an electric power gainvalue of the transmission signal is periodically changed, no distortionoccurs in a waveform of a transient response, and a band of thetransmission signal is not widened. Accordingly, an electric power ofthe transmission signal can be prevented from being leaked to a signalof an adjacent frequency channel.

In a signal processing device of a multiplex communication according tothe present invention, the changeover signal indicating the changeoverof the waveform reshaping means is sent to the selecting means by thesignal generating means in response to the reception of an instructionwhich indicates the change of the electric power gain value of thetransmission signal.

Therefore, even though a channel gain denoting an electric power gainvalue of the transmission signal is arbitrarily changed, no distortionoccurs in a waveform of a transient response, and a band of thetransmission signal is not widened. Accordingly, an electric power ofthe transmission signal can be prevented from being leaked to a signalof an adjacent frequency channel.

In a signal processing device of a multiplex communication according tothe present invention, the information signals sent in a plurality oftransmission channels are modulated by the modulating means to producethe modulated signals corresponding to a plurality of systems.

Therefore, in cases where pieces of information of a plurality ofsystems are simultaneously transmitted from a communication terminaldevice, even though a channel gain denoting an electric power gain valueof the transmission signal is arbitrarily changed, no distortion occursin a waveform of a transient response, and a band of the transmissionsignal is not widened. Accordingly, an electric power of thetransmission signal can be prevented from being leaked to signals of thepieces of information of the systems near to that of the transmissionsignal.

In a signal processing device of a multiplex communication according tothe present invention, the electric power controlled signals of thefirst and second groups are added together by the adding means toproduce the composite modulation signal corresponding to thetransmission signal which is transmitted from a mobile station to a basestation.

Therefore, in cases where the signal processing device is applied for amobile communication system, even though a channel gain denoting anelectric power gain value of the transmission signal is arbitrarilychanged, no distortion occurs in a waveform of a transient response, anda band of the transmission signal is not widened. Accordingly, anelectric power of the transmission signal can be prevented from beingleaked to a signal of an adjacent frequency channel.

A signal processing device of a multiplex communication according to thepresent invention comprises modulating means for performing a spreadingmodulation for a plurality of information signals sent in a transmissionchannel according to codes to produce a plurality of modulated signalsfor CDMA communication, waveform reshaping means of first and secondgroups for reshaping waveforms of the modulated signals to produce aplurality of reshaped modulation signals, selecting means for selectingthe waveform reshaping means of the first group or the waveformreshaping means of the second group according to a changeover signal andreceiving the modulated signals output from the modulating means,multiplying means of the first and second groups, which correspond tothe waveform reshaping means of the first and second groupsrespectively, for multiplying each reshaped modulation signal producedby the waveform reshaping means of the corresponding group by a gainsignal for each of the first and second groups to produce a plurality ofelectric power controlled signals, adding means for adding together theelectric power controlled signals produced by the multiplying means ofthe first and second groups to produce a composite modulation signalcorresponding to a transmission signal, and signal generating means forsending the changeover signal, which indicates the changeover from thewaveform reshaping means of the first group corresponding to thereception of the modulated signals to the waveform reshaping means ofthe second group, to the selecting means in cases where an electricpower gain value of the transmission signal is changed, generating a newgain signal of which a new electric power gain value is changed from anelectric power gain value of the gain signal, sending the new gainsignal to the multiplying means corresponding to the waveform reshapingmeans of the second group, and successively sending the gain signalhaving the electric power gain value to the multiplying meanscorresponding to the waveform reshaping means of the first group duringa prescribed time period after the change of the gain signal to the newgain signal.

Therefore, in cases where the signal processing device is applied for aCDMA communication system, even though a channel gain denoting anelectric power gain value of the transmission signal is changedstepwise, no distortion occurs in a waveform of a transient response,and a band of the transmission signal is not widened. Accordingly, anelectric power of the transmission signal can be prevented from beingleaked to a signal of an adjacent frequency channel.

A signal processing method of a multiplex communication according to thepresent invention comprises a step of reshaping waveforms of a pluralityof modulated signals in waveform reshaping means of first and secondgroups, a step of selecting the waveform reshaping means of the firstgroup or the waveform reshaping means of the second group according to achangeover signal, a step of receiving the modulated signals, a step ofmultiplying, in multiplying means of the first and second groups whichcorrespond to the waveform reshaping means of the first and secondgroups respectively, each of a plurality of reshaped modulation signalsreceived from the waveform reshaping means of the corresponding group bya received gain signal for each of the first and second groups toproduce a plurality of electric power controlled signals of the firstand second groups, a step of adding together the electric powercontrolled signals of the first and second groups to produce a compositemodulation signal corresponding to a transmission signal, a step ofgenerating the changeover signal, which indicates the changeover fromthe waveform reshaping means of the first group corresponding to thereception of the modulated signals to the waveform reshaping means ofthe second group, in cases where an electric power gain value of thetransmission signal is changed, to select the waveform reshaping meansof the second group, a step of generating a new gain signal of which anew electric power gain value is changed from an electric power gainvalue of the gain signal, a step of sending the new gain signal to themultiplying means corresponding to the waveform reshaping means of thesecond group, and a step of successively sending the gain signal havingthe electric power gain value to the multiplying means corresponding tothe waveform reshaping means of the first group during a prescribed timeperiod after the change of the gain signal to the new gain signal.

Therefore, even though a channel gain denoting an electric power gainvalue of the transmission signal is changed stepwise, no distortionoccurs in a waveform of a transient response, and a band of thetransmission signal is not widened. Accordingly, an electric power ofthe transmission signal can be prevented from being leaked to a signalof an adjacent frequency channel.

In a signal processing method of a multiplex communication according tothe present invention, the gain signal having the electric power gainvalue is successively sent to the multiplying means corresponding to thewaveform reshaping means of the first group in the step of generatingthe changeover signal and the gain signal until a transient response ofthe waveform reshaping means of the first group is completed.

Therefore, even though a channel gain denoting an electric power gainvalue of the transmission signal is changed stepwise, no distortionoccurs in a waveform of a transient response, and a band of thetransmission signal is not widened. Accordingly, an electric power ofthe transmission signal can be prevented from being leaked to a signalof an adjacent frequency channel.

In a signal processing method of a multiplex communication according tothe present invention, the changeover signal indicating the changeoverof the waveform reshaping means is periodically generated by the signalgenerating means in the step of generating the changeover signal and thegain signal.

Therefore, even though a channel gain denoting an electric power gainvalue of the transmission signal is periodically changed, no distortionoccurs in a waveform of a transient response, and a band of thetransmission signal is not widened. Accordingly, an electric power ofthe transmission signal can be prevented from being leaked to a signalof an adjacent frequency channel.

In a signal processing method of a multiplex communication according tothe present invention, the changeover signal indicating the changeoverof the waveform reshaping means is sent out to select the waveformreshaping means of the second group in the step of generating thechangeover signal and the gain signal in response to the reception of aninstruction which indicates the change of the electric power gain valueof the transmission signal.

Therefore, even though a channel gain denoting an electric power gainvalue of the transmission signal is arbitrarily changed, no distortionoccurs in a waveform of a transient response, and a band of thetransmission signal is not widened. Accordingly, an electric power ofthe transmission signal can be prevented from being leaked to a signalof an adjacent frequency channel.

In a signal processing method of a multiplex communication according tothe present invention, the information signals sent in a plurality oftransmission channels are modulated in the step of producing themodulated signals.

Therefore, in cases where pieces of information of a plurality ofsystems are simultaneously transmitted from a communication terminaldevice, even though a channel gain denoting an electric power gain valueof the transmission signal is arbitrarily changed, no distortion occursin a waveform of a transient response, and a band of the transmissionsignal is not widened. Accordingly, an electric power of thetransmission signal can be prevented from being leaked to signals of thepieces of information of the systems near to that of the transmissionsignal.

In a signal processing method of a multiplex communication according tothe present invention, the electric power controlled signals of thefirst and second groups are added together, in the step of producing thecomposite modulation signal, to produce the composite modulation signalcorresponding to the transmission signal which is transmitted from amobile station to a base station.

Therefore, in cases where the signal processing device is applied for amobile communication system, even though a channel gain denoting anelectric power gain value of the transmission signal is arbitrarilychanged, no distortion occurs in a waveform of a transient response, anda band of the transmission signal is not widened. Accordingly, anelectric power of the transmission signal can be prevented from beingleaked to a signal of an adjacent frequency channel.

In a signal processing method of a multiplex communication according tothe present invention, a spreading modulation is performed for theinformation signals sent in the transmission channel according to codesin the step of producing the modulated signals to produce a plurality ofmodulated signals for CDMA communication.

Therefore, in cases where the signal processing device is applied for aCDMA communication system, even though a channel gain denoting anelectric power gain value of the transmission signal is changedstepwise, no distortion occurs in a waveform of a transient response,and a band of the transmission signal is not widened. Accordingly, anelectric power of the transmission signal can be prevented from beingleaked to a signal of an adjacent frequency channel.

In a signal processing method of a multiplex communication according tothe present invention, the composite modulation signal corresponding tothe transmission signal, which is transmitted from a mobile station to abase station corresponding to the CDMA communication, is produced in thestep of producing the composite modulation signal.

Therefore, in cases where the signal processing device is applied for aCDMA communication system, even though a channel gain denoting anelectric power gain value of the transmission signal is changedstepwise, no distortion occurs in a waveform of a transient response,and a band of the transmission signal is not widened. Accordingly, anelectric power of the transmission signal can be prevented from beingleaked to a signal of an adjacent frequency channel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a conventional signal processing device ina CDMA communication system.

FIG. 2 is a view showing waveforms of signals shown in FIG. 1.

FIG. 3 is a block diagram of a signal processing device in a CDMAcommunication system according to a first embodiment of the presentinvention.

FIG. 4 is a view showing waveforms of signals shown in FIG. 3.

FIG. 5 is a view showing waveforms of signals shown in FIG. 3.

FIG. 6 is a view showing waveforms of signals shown in FIG. 3.

FIG. 7 is a view showing waveforms of signals shown in FIG. 3.

FIG. 8 is a view showing waveforms of signals shown in FIG. 3.

FIG. 9 is a view showing waveforms of signals shown in FIG. 3.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the best mode for carrying out the present invention willnow be described with reference to the accompanying drawings to explainthe present invention in more detail.

Embodiment 1

FIG. 3 is a block diagram of a signal processing device in a CDMAcommunication system according to a first embodiment of the presentinvention.

In FIG. 3, 1 indicates a spreading modulating unit for performing adirect spreading modulation for two input signals of two channels CH1and CH2 as a spreading modulation according to two pseudo noise signalsinput from Code 1 and Code 2. The spreading modulating unit 1 iscomposed of four exclusive logical sum (OR) gates 1 a, 1 b, 1 c and 1 d.2 indicates a channel gain setting unit for producing four channel gainsetting signals of two groups and a filter changeover signal accordingto two channel gains βd and βc received from the outside.

3 indicates a filter selecting unit for selecting one of two groupsaccording to the filter changeover signal received from the channel gainsetting unit 2 and sending four modulated signals received from thespreading modulating unit 1 to the selected group. The filter selectingunit 3 is composed of four changeover switches 3 a, 3 b, 3 c and 3 d. 4to 7 indicate four waveform reshaping units of one group (or a firstgroup) for receiving the modulated signals from the filter selectingunit 3 in cases where the group is selected in the filter selecting unit3. 8 to 11 indicate four waveform reshaping units of the other group (ora second group) for receiving the modulated signals from the filterselecting unit 3 in cases where the group is selected in the filterselecting unit 3.

12 to 19 indicate eight channel gain multipliers (hereinafter, calledmultipliers) for respectively multiplying a reshaped modulation signal,which is obtained by performing the waveform reshaping for one modulatedsignal in one of the waveform reshaping units 4 to 11, by a channel gainof one channel gain setting signal received from the channel gainsetting unit 2. 20 indicates an adder for adding together signalsreceived from the multipliers 12 and 13. 21 indicates an adder foradding together signals received from the multipliers 14 and 15. 22indicates an adder for adding together signals received from themultipliers 16 and 17. 23 indicates an adder for adding together signalsreceived from the multipliers 18 and 19. 24 indicates a channel adder(hereinafter, called an adder) for adding together signals received fromthe adders 20 and 22. 25 indicates a channel adder (hereinafter, calledan adder) for adding together signals received from the adders 21 and23.

Next, an operation of the signal processing device shown in FIG. 3 willbe described below.

Two types of signals (for example, an audio signal and a data signal) oftwo transmission channels CH1 and CH2 are received in the spreadingmodulating unit 1. The signal of the channel CH1 is received in theexclusive OR gates 1 a and 1 c, and the signal of the channel CH2 isreceived in the exclusive OR gates 1 b and 1 d.

Also, a pseudo noise signal of the Code 1 is received in the exclusiveOR gates 1 a and 1 d, and a pseudo noise signal of the Code 2 isreceived in the exclusive OR gates 1 b and 1 c.

Therefore, the QPSK modulation is performed for the two types of signalsof the transmission channels CH1 and CH2 in the exclusive OR gates 1 ato 1 d, and a frequency band of each signal is spread to a spreadfrequency band which is tens times of the frequency band. In this case,the signals of the channels CH1 and CH2 are modulated in the exclusiveOR gates 1 a to 1 d to produce four modulated signals I_(CH1), I_(CH2),Q_(CH1) and Q_(CH2) according to following multiplication equations.I _(CH1) =CH 1×Code 1I _(CH2) =−CH 2×Code 2Q _(CH1) =CH 1×Code 2Q _(CH2) =CH 2×Code 1

The modulated signals I_(CH1), I_(CH2), Q_(CH1) and Q_(CH2) areorthogonal to each other. The modulated signals I_(CH1), I_(CH2),Q_(CH1) and Q_(CH2) spread in the exclusive OR gates 1 a to 1 d areinput to input contact points of the changeover switches 3 a, 3 b, 3 cand 3 d of the filter selecting unit 3 respectively. In the changeoverswitches 3 a, 3 b, 3 c and 3 d, the input contact points are connectedwith a group of output contact points #1 or a group of output contactpoints #2 according to the filter changeover signal sent from thechannel gain setting unit 2. The output contact points #1 of thechangeover switches 3 a, 3 b, 3 c and 3 d are connected with thewaveform reshaping units 4, 5, 6 and 7 respectively, and the outputcontact points #2 of the changeover switches 3 a, 3 b, 3 c and 3 d areconnected with the waveform reshaping units 8, 9, 10 and 11respectively.

Therefore, in cases where the input contact points of the changeoverswitches 3 a, 3 b, 3 c and 3 d are connected with the output contactpoints #1, the modulated signals I_(CH1), I_(CH2), Q_(CH1) and Q_(CH2)are received in the waveform reshaping units 4, 5, 6 and 7 respectivelyin time sharing. Also, in cases where the input contact points of thechangeover switches 3 a, 3 b, 3 c and 3 d are connected with the outputcontact points #2, the modulated signals I_(CH1), I_(CH2), Q_(CH1) andQ_(CH2) are received in the waveform reshaping units 8, 9, 10 and 11respectively in time sharing.

In this case, a signal having an amplitude of 0 is supplied to one groupof output contact points with which no input contact points areconnected. Therefore, a data string of each modulated signal I_(CH1),I_(CH2), Q_(CH1) or Q_(CH2) output from the filter selecting unit 3 isexpressed by a 2-bit data string in which one bit denoting the amplitudeof 0 is added to the modulated signal I_(CH1), I_(CH2), Q_(CH1) orQ_(CH2).

Here, the modulated signals received in the waveform reshaping units 4,5, 6 and 7 are expressed by I_(CH1#1), I_(CH2#1), Q_(CH1#1) andQ_(CH2#1) respectively, and the modulated signals received in thewaveform reshaping units 8, 9, 10 and 11 are expressed by I_(CH1#2),I_(CH2#2), Q_(CH1#2) and Q_(CH2#2) respectively.

Thereafter, waveform reshaping is performed for the modulated signalI_(CH1#1) of the channel 1 and I component, the modulated signalI_(CH2#1) of the channel 2 and I component, the modulated signalQ_(CH1#1) of the channel 1 and Q component and the modulated signalQ_(CH2#1) of the channel 2 and Q component output from the filterselecting unit 3 in the waveform reshaping units 4, 5, 6 and 7, andwaveform reshaping is performed for the modulated signal I_(CH1#2) ofthe channel 1 and I component, the modulated signal I_(CH2#2) of thechannel 2 and I component, the modulated signal Q_(CH1#2) of the channel1 and Q component and the modulated signal Q_(CH2#2) of the channel 2and Q component output from the filter selecting unit 3 in the waveformreshaping units 8, 9, 10 and 11. Therefore, a multi-bit data string of areshaped modulation signal satisfying a desired amplitude precision isoutput from each waveform reshaping unit. Here, the reshaped modulationsignals output from the waveform reshaping units 4, 5, 6 and 7 areexpressed by I′_(CH1#1), I′_(CH2#1), Q′_(CH1#1) and Q′_(CH2#1)respectively, and the reshaped modulation signals output from thewaveform reshaping units 8, 9, 10 and 11 are expressed by I′_(CH1#2),I′_(CH2#2), Q′_(CH1#2) and Q′_(CH2#2) respectively.

Thereafter, the reshaped modulation signals output from the waveformreshaping units 4 to 11 are received in the multipliers 12 to 19respectively. Also, channel gains of the channel gain setting signalsoutput from the channel gain setting unit 2 are received in themultipliers 12 to 19 respectively.

That is, a channel gain βd#1 is received in the multiplier 12, a channelgain βc#1 is received in the multiplier 13, the channel gain βd#1 isreceived in the multiplier 14, the channel gain βc#1 is received in themultiplier 15, a channel gain βd#2 is received in the multiplier 16, achannel gain βc#2 is received in the multiplier 17, the channel gainβd#2 is received in the multiplier 18 and the channel gain.

βc#2 is received in the multiplier 19. Thereafter, the reshapedmodulation signal is multiplied by the channel gain in each multiplier,and an electric power controlled modulation signal is output from eachmultiplier.

Thereafter, the electric power controlled modulation signals output fromthe multipliers 12 and 13 are added together in the adder 20, theelectric power controlled modulation signals output from the multipliers14 and 15 are added together in the adder 21, the electric powercontrolled modulation signals output from the multipliers 16 and 17 areadded together in the adder 22, and the electric power controlledmodulation signals output from the multipliers 18 and 19 are addedtogether in the adder 23. Thereafter, an output of the adder 20 and anoutput of the adder 22 are added together in the adder 24, and an outputof the adder 21 and an output of the adder 23 are added together in theadder 25.

As a result, a modulation signal Imod of the I component is output fromthe adder 24, and a modulation signal Qmod of the Q component is outputfrom the adder 25. Therefore, The modulation signals Imod and Qmod areindicated according to following equations.Imod=βd _(#1) ×I′ _(CH1#1) +βc _(#1) ×I′ _(CH2#1) +βd _(#2) ×I′ _(CH1#2)+βc _(#2) ×I′ _(CH2#2)Qmod=βd _(#1) ×Q′ _(CH1#1) +βc _(#1) ×Q′ _(CH2#1) +βd _(#2) ×Q′ _(CH1#2)+βc _(#2) ×Q′ _(CH2#2)

In these equations, assuming that the channel gains are the same as eachother,βd=βd _(#1) =βd _(#2)βc=βc _(#1) =βc _(#2)are set. Therefore,Imod=βd×(I′ _(CH1#1) +I′ _(CH1#2))+βc×(I′ _(CH2#1) +I′ _(CH2#2))Qmod=βd×(Q′ _(CH1#1) +Q′ _(CH1#2))+βc×(Q′ _(CH2#1) +Q′ _(CH2#2))are obtained. Also,I _(CH1) =I _(CH1#1) +I _(CH1#2)I _(CH2) =I _(CH2#1) +I _(CH2#2)Q _(CH1) =Q _(CH1#1) +Q _(CH1#2)Q _(CH2) =Q _(CH2#1) +Q _(CH2#2)are satisfied. Therefore,I′ _(CH1) =I′ _(CH1#1) +I′ _(CH1#2)I′ _(CH2) =I′ _(CH2#1) +I′ _(CH2#2)Q′ _(CH1) =Q′ _(CH1#1) +Q′ _(CH1#2)Q′ _(CH2) =Q′ _(CH2#1) +Q′ _(CH2#2)are obtained. Therefore,Imod=βd×I′ _(CH1) +βc×I′ _(CH2)Qmod=βd×Q′ _(CH1) +βc×Q′ _(CH2)are satisfied. Therefore, in cases where no channel gains are changed,the same modulation signals Imod and Qmode as those in the prior art areoutput from the signal processing device shown in FIG. 3.

FIG. 4 is a view showing a filter changeover signal a sent from thechannel gain setting unit 2 to the filter selecting unit 3 at constantperiods T, changes of the channel gains βc and βd sent from the outsideto the channel gain setting unit 2 at the constant periods T and changesof the channel gains βc_(#1), βc_(#2), βd_(#1) and βd_(#2) sent from thechannel gain setting unit 2 to the multipliers 12 to 19.

As shown in FIG. 4, the channel gain βc is changed to βc(n), βc(n+1),βc(n+2), βc(n+3), βc(n+4), - - - one after another in that order everyconstant time period T, and the channel gain βd is changed to βd(n),βd(n+1), βd(n+2), βd(n+3), βd(n+4), - - - one after another in thatorder every constant time period T. In this case, it is not necessarilyrequired to change a value (or an electric power gain value) of thechannel gain every constant time period T. That is, it is applicablethat the value of the channel gain be constant during a plurality ofconstant time periods.

In the time period T of the first cycle in FIG. 4, the filter changeoversignal a of the channel gain setting unit 2 indicates the group ofoutput contact points #1. That is, the filter changeover signal aindicates the selection of the waveform reshaping units 4, 5, 6 and 7 towhich the modulated signals output from the spreading modulating unit 1are input respectively. Also, the channel gains βc(n) and βd(n) are setas the channel gains βc_(#1) and βd_(#1) input to the multipliers 12,13, 14 and 15 corresponding to the selected waveform reshaping units 4,5, 6 and 7.

In the time period T of the second cycle, the filter changeover signal aof the channel gain setting unit 2 indicates the group of output contactpoints #2. That is, the filter changeover signal a indicates theselection of the waveform reshaping units 8, 9, 10 and 11 to which themodulated signals output from the spreading modulating unit 1 are inputrespectively. Also, the channel gains βc(n+1) and βd(n+1) are set as thechannel gains βc_(#2) and βd_(#2) input to the multipliers 16, 17, 18and 19 corresponding to the selected waveform reshaping units 8, 9, 10and 11. In this case, the channel gains βc(n) and βd(n) in the firstcycle are maintained during the time period T of the second cycle as thechannel gains βc_(#1) and βd_(#1) input to the multipliers 12, 13, 14and 15.

The channel gains βc and βd are maintained until the transient responsesof the waveform reshaping units 4, 5, 6 and 7 (or the waveform reshapingunits 8, 9, 10 and 11) are completed. Also, the time period T is equalto a changing cycle of the channel gains βc and βd or is equal to 1/N (Ndenotes a positive integral number) of the changing cycle of the channelgains βc and βd.

FIG. 5 and FIG. 6 are timing charts of signal waveforms in case of nochange of the channel gains. Signs attached to the heads of the signalwaveforms correspond to those attached to signal lines in FIG. 3. Thatis, the signal waveforms a to m in FIG. 5 indicate the filter changeoversignal a of the channel gain setting unit 2, the signal b input to thewaveform reshaping unit 4, the signal c input to the waveform reshapingunit 5, the signal d input to the waveform reshaping unit 8, the signale input to the waveform reshaping unit 9, the signal f output from thewaveform reshaping unit 4, the signal g output from the waveformreshaping unit 5, the signal h output from the adder 20, the signal ioutput from the waveform reshaping unit 8, the signal j output from thewaveform reshaping unit 9, the signal k output from the adder 22 and thesignal m output from the adder 24.

Also, the signal waveforms n to y in FIG. 6 indicate the signal n inputto the waveform reshaping unit 6, the signal p input to the waveformreshaping unit 7, the signal q input to the waveform reshaping unit 10,the signal r input to the waveform reshaping unit 11, the signal soutput from the waveform reshaping unit 6, the signal t output from thewaveform reshaping unit 7, the signal u output from the adder 21, thesignal v output from the waveform reshaping unit 10, the signal w outputfrom the waveform reshaping unit 11, the signal x output from the adder23 and the signal y output from the adder 25.

In FIG. 5 and FIG. 6, the group of output contact points #1 and thegroup of output contact points #2 are alternately indicated by thefilter changeover signal a at the time periods T. Therefore, the sendingof the input signals b, c, d and e to the group corresponding to thegroup of output contact points #1 and the sending of the input signalsn, p, q and r to the group corresponding to the group of output contactpoints #2 are performed in the filter selecting unit 3 in time sharing.Also, a signal having an amplitude of 0 is input to each waveformreshaping unit during a time period in which no input signal is sent tothe waveform reshaping unit. Thereafter, the waveforms of the inputsignals b, c, d, e, n, p, q and r are reshaped in the waveform reshapingunits 4 to 11 respectively. In this case, as shown in the waveforms f,g, i, j, s, t, v and w, when the sending of the modulated signals fromthe filter selecting unit 3 is started, an output electric power of thereshaped modulation signal output from each waveform reshaping unit isincreased according to a step response of the waveform reshaping unitand reaches a constant value in a stationary state. Thereafter, when thesending of the modulated signals from the filter selecting unit 3 iscompleted and a signal having an amplitude of 0 is sent to the waveformreshaping units, the output electric power of the reshaped modulationsignal output from each waveform reshaping unit is decreased accordingto the step response of the waveform reshaping unit and reaches aconstant value in a stationary state.

Thereafter, the output electric power of each reshaped modulation signalis multiplied by the corresponding channel gain in the correspondingmultiplier 12 to 19, and adding results are obtained in the adders 20 to23. The adding results are indicated by the waveforms of the signals h,k, u and x. Thereafter, the waveforms of the signals h and k output fromthe adders 20 and 22 are added together in the adder 24, and thewaveform signal Imode (=m) denoting the I component of a modulationsignal having an almost constant amplitude is produced. Also, thewaveforms of the signals u and x output from the adders 21 and 23 areadded together in the adder 25, and the waveform signal Qmode (=y)denoting the Q component of the modulation signal having the almostconstant amplitude is produced.

Accordingly, the waveform signals Imode and Qmode of the same modulationsignal as that obtained in the prior art, in which each reshapedmodulation signal is multiplied by the same channel gain as that of thefirst embodiment, are obtained.

FIG. 7 is a view showing signal waveforms in case of the change of onechannel gain. To simplify the description of the case shown in FIG. 7,the channel gain βd of the channel CH1 is changed to βd1, βd2, βd3 andβd4 one after another in that order every time period T in this case.That is, waveforms of signals relating to only the I component are shownin FIG. 7.

In the time period T of the first cycle in which the channel gain βd1 isreceived from the outside as the channel gain βd, the waveform reshapingunit 4 is selected to process the modulated signal of the I component inthe channel CH1. A band limit is performed for the signal b input to thewaveform reshaping unit 4 in this cycle, and the signal f is output fromthe waveform reshaping unit 4. Also, the channel gain βd1 is received inthe multiplier 12 as the channel gain βd1#1 during both this cycle and anext cycle. A multiplied result of the multiplier 12 is included in thesignal h output from the adder 20.

That is, as shown by arrows in FIG. 7, the channel gains βd1 and βd2 areincorporated in the signals h and k respectively, and the channel gainsβd1 and βd2 are successively used for the multiplication until thetransient response of the waveform reshaping unit 4 is completed.Therefore, no distortion occurs in the signal f output from the waveformreshaping unit 4, and the output signal h of the adder 20 is obtained byadding together both a signal, which is obtained by multiplying a bandlimited signal output from the waveform reshaping unit 4 by the channelgain βd1, and a signal output from the multiplier 12. In the samemanner, the signal relating to the Q component of the channel CH1 isobtained.

As is described above, in the first embodiment, because all signalsincluded in each cycle T are respectively multiplied by a channel gain,no distortion occurs in the signal output from each adder. Therefore, nodistortion occurs in the signal output from the adder 24 as a result ofthe addition of the signals corresponding to the output contact points#1 and the signals corresponding to the output contact points #2.Accordingly, even though a channel gain is changed, each of the bandwidth of the waveform signal Imode and the band width of the waveformsignal Qmode is not widened. As a result, an electric power of atransmission signal can be prevented from being leaked to a signal of anadjacent frequency channel.

Embodiment 2

The configuration of a signal processing device according to a secondembodiment is the same as that according to the first embodiment.Therefore, additional description of the signal processing device isomitted.

In the second embodiment, an operation of the channel gain setting unit2 differs from that of the first embodiment. In the second embodiment,the filter changeover signal a is not sent to the filter selecting unit3 at constant time periods, but the filter changeover signal a is sentto the filter selecting unit 3 when an instruction indicating a changeof an electric power of a transmission signal is received in the channelgain setting unit 2.

FIG. 8 shows a change of a value of the channel gain βc of the channelCH2.

The channel gains βc and βd input from the outside to the channel gainsetting unit 2 are always monitored in the channel gain setting unit 2.When it is detected that a value of the channel gain βc or βd is changedto a new value, the filter changeover signal a indicating the selectionof the output contact points #1 is changed to the filter changeoversignal a indicating the selection of the output contact points #2 by thechannel gain setting unit 2, and the value of the channel gain βc or βdreceived in the multiplier corresponding to each waveform reshapingunit, in which the modulated signal output from the spreading modulatingunit 1 is received according to the changed filter changeover signal a,is changed to the new value of the changed channel gain βc or βd. Forexample, as shown in FIG. 8, the channel gain βc received in the channelgain setting unit 2 is changed to the channel gain βc′, and the channelgain βc#2 received in the multiplier 19 is changed to the channel gainβc′.

FIG. 9 shows waveforms of signals relating to the I component of thechannel CH1 in case of a change of the channel gain βd from βd1 to βd2.a sign attached to a head of a waveform of each signal corresponds to asignal line of FIG. 3 indicated by the sign. In a time period ofreceiving the channel gain βd1 from the outside as the channel gain βd,the waveform reshaping unit 4 corresponding to the I component and thechannel 1 is selected. Therefore, a band limit is performed for themodulated signal input to the waveform reshaping unit 4. Also, thechannel gain βd1 is input to the multiplier 12 corresponding to thewaveform reshaping unit 4 as the channel gain βd#1. The inputting of thechannel gain βd1 to the multiplier 12 is continued after the change ofthe filter changeover signal a indicating the selection of the outputcontact points #1 to the filter changeover signal a indicating theselection of the output contact points #2.

As a result, as shown by arrows in FIG. 9, the channel gain βd1 input tothe multiplier 12 is incorporated in the electric power of the signal houtput from the adder 20, and the channel gain βd1 is successively usedfor the multiplication until the transient response of the waveformreshaping unit 4 is completed. Therefore, no distortion occurs in thesignal f output from the waveform reshaping unit 4, and the outputsignal h of the adder 20 is obtained by adding together both a signal,which is obtained by multiplying a band limited signal output from thewaveform reshaping unit 4 by the channel gain βd1, and a signal outputfrom the multiplier 12. In the same manner, the signal relating to the Qcomponent of the channel CH1 is obtained.

As is described above, in the second embodiment, even though the filterchangeover signal a indicating the selection of the output contactpoints #1 is changed to the filter changeover signal a indicating theselection of the output contact points #2 when a value of a channel gainsent from the outside is changed to a new value, a signal output fromeach waveform reshaping unit corresponding to the output contact point#1 is multiplied, after the change of the filter changeover signal a, bythe channel gain by which the signal is multiplied before the change ofthe filter changeover signal a. Therefore, no distortion occurs in thewaveform of the signal output from each signal, and no distortion occursin the signal output from the adder 24 as a result of the addition ofthe signals corresponding to the output contact points #1 and thesignals corresponding to the output contact points #2. Accordingly, eventhough a channel gain is changed, each of the band width of the waveformsignal Imode and the band width of the waveform signal Qmode is notwidened.

In the first and second embodiments, each channel gain denoting anelectric power gain value of a gain signal is received from the outside.However, it is applicable that the channel gains be stored in advance inthe signal processing device.

Also, in the first and second embodiments, the present invention isdescribed by adopting an example of the direct spreading in the CDMAcommunication system. However, it is applicable that a frequency hoppingor another spreading be adopted.

Also, in the first and second embodiments, the signal processing deviceand the signal processing method in the CDMA communication system aredescribed. However, a technical scope in the present invention is notlimited to the CDMA communication system. That is, in addition to theFDMA communication system and the TDMA communication system, the presentinvention can be applied for all types of systems in which signalprocessing is performed for a signal, for which a band limit isperformed by superposing an impulse response on the signal, whilechanging a gain for the signal stepwise. Therefore, even though the gainis changed during the impulse response, distortion can be prevented fromoccurring in a waveform of the signal.

INDUSTRIAL APPLICABILITY

As is described above, in the signal processing device and the signalprocessing method applied for the CDMA communication system, even thougha channel gain denoting an electric power gain value of a gain signal ischanged stepwise, no distortion occurs in a waveform of a transientresponse, and a band of a transmission signal is not widened. Therefore,the increase of an electric power leaked to a signal of an adjacentfrequency channel can be suppressed. Accordingly, the signal processingdevice and the signal processing method are appropriate for the CDMAcommunication system and another type of multiplex communication system.

1. A signal processing device of a multiplex communication, comprising:modulating means for modulating a plurality of information signals ofmultiplex communication sent in a transmission channel to produce aplurality of modulated signals; waveform reshaping means of first andsecond groups for reshaping waveforms of the modulated signals toproduce a plurality of reshaped modulation signals; selecting means forselecting the waveform reshaping means of the first group or thewaveform reshaping means of the second group according to a changeoversignal and receiving the modulated signals produced by the modulatingmeans; multiplying means of the first and second groups, whichcorrespond to the waveform reshaping means of the first and secondgroups respectively, for multiplying each reshaped modulation signalproduced by the waveform reshaping means of the corresponding group by again signal for each of the first and second groups to produce aplurality of electric power controlled signals; adding means for addingtogether the electric power controlled signals produced by themultiplying means of the first and second groups to produce a compositemodulation signal corresponding to a transmission signal; and signalgenerating means for generating the changeover signal, which indicatesthe changeover from the waveform reshaping means of the first groupcorresponding to the reception of the modulated signals to the waveformreshaping means of the second group, in cases where an electric powergain value of the transmission signal is changed, sending the changeoversignal to the selecting means, generating a new gain signal of which anew electric power gain value is changed from an electric power gainvalue of the gain signal, sending the new gain signal to the multiplyingmeans corresponding to the waveform reshaping means of the second group,and successively sending the gain signal having the electric power gainvalue to the multiplying means corresponding to the waveform reshapingmeans of the first group during a prescribed time period after thechange of the gain signal to the new gain signal.
 2. A signal processingdevice of a multiplex communication according to claim 1, wherein thegain signal having the electric power gain value is successively sent tothe multiplying means corresponding to the waveform reshaping means ofthe first group by the signal generating means until a transientresponse of the waveform reshaping means of the first group iscompleted.
 3. A signal processing device of a multiplex communicationaccording to claim 1, wherein the changeover signal indicating thechangeover of the waveform reshaping means is periodically generated bythe signal generating means and is sent to the selecting means.
 4. Asignal processing device of a multiplex communication according to claim1, wherein the changeover signal indicating the changeover of thewaveform reshaping means is sent to the selecting means by the signalgenerating means in response to the reception of an instruction whichindicates the change of the electric power gain value of thetransmission signal.
 5. A signal processing device of a multiplexcommunication according to claim 1, wherein the information signals sentin a plurality of transmission channels are modulated by the modulatingmeans to produce the modulated signals corresponding to a plurality ofsystems.
 6. A signal processing device of a multiplex communicationaccording to claim 1, wherein the electric power controlled signals ofthe first and second groups are added together by the adding means toproduce the composite modulation signal corresponding to thetransmission signal which is transmitted from a mobile station to a basestation.
 7. A signal processing device of a multiplex communication,comprising: modulating means for performing a spreading modulation for aplurality of information signals sent in a transmission channelaccording to codes to produce a plurality of modulated signals for CDMAcommunication; waveform reshaping means of first and second groups forreshaping waveforms of the modulated signals to produce a plurality ofreshaped modulation signals; selecting means for selecting the waveformreshaping means of the first group or the waveform reshaping means ofthe second group according to a changeover signal and receiving themodulated signals output from the modulating means; multiplying means ofthe first and second groups, which correspond to the waveform reshapingmeans of the first and second groups respectively, for multiplying eachreshaped modulation signal produced by the waveform reshaping means ofthe corresponding group by a gain signal for each of the first andsecond groups to produce a plurality of electric power controlledsignals; adding means for adding together the electric power controlledsignals produced by the multiplying means of the first and second groupsto produce a composite modulation signal corresponding to a transmissionsignal; and signal generating means for sending the changeover signal,which indicates the changeover from the waveform reshaping means of thefirst group corresponding to the reception of the modulated signals tothe waveform reshaping means of the second group, to the selecting meansin cases where an electric power gain value of the transmission signalis changed, generating a new gain signal of which a new electric powergain value is changed from an electric power gain value of the gainsignal, sending the new gain signal to the multiplying meanscorresponding to the waveform reshaping means of the second group, andsuccessively sending the gain signal having the electric power gainvalue to the multiplying means corresponding to the waveform reshapingmeans of the first group during a prescribed time period after thechange of the gain signal to the new gain signal.
 8. A signal processingdevice of a multiplex communication according to claim 7, wherein thegain signal having the electric power gain value is successively sent tothe multiplying means corresponding to the waveform reshaping means ofthe first group by the signal generating means until a transientresponse of the waveform reshaping means of the first group iscompleted.
 9. A signal processing device of a multiplex communicationaccording to claim 7, wherein the changeover signal indicating thechangeover of the waveform reshaping means is periodically generated bythe signal generating means and is sent to the selecting means.
 10. Asignal processing device of a multiplex communication according to claim7, wherein the changeover signal indicating the changeover of thewaveform reshaping means is generated and sent to the selecting means bythe signal generating means in response to the reception of aninstruction which indicates the change of the electric power gain valueof the transmission signal.
 11. A signal processing device of amultiplex communication according to claim 7, wherein the spreadingmodulation is performed for the information signals sent in a pluralityof transmission channels by the modulating means.
 12. A signalprocessing device of a multiplex communication according to claim 7,wherein the electric power controlled signals of the first and secondgroups are added together by the adding means to produce the compositemodulation signal corresponding to the transmission signal which istransmitted from a mobile station to a base station corresponding to theCDMA communication.
 13. A signal processing method of a multiplexcommunication, comprising: a step of modulating a plurality ofinformation signals of multiplex communication sent in a transmissionchannel to produce a plurality of modulated signals; a step of reshapingwaveforms of the modulated signals in waveform reshaping means of firstand second groups; a step of selecting the waveform reshaping means ofthe first group or the waveform reshaping means of the second groupaccording to a changeover signal; a step of receiving the modulatedsignals; a step of multiplying, in multiplying means of the first andsecond groups which correspond to the waveform reshaping means of thefirst and second groups respectively, each of a plurality of reshapedmodulation signals received from the waveform reshaping means of thecorresponding group by a received gain signal for each of the first andsecond groups to produce a plurality of electric power controlledsignals of the first and second groups; a step of adding together theelectric power controlled signals of the first and second groups toproduce a composite modulation signal corresponding to a transmissionsignal; a step of generating the changeover signal, which indicates thechangeover from the waveform reshaping means of the first groupcorresponding to the reception of the modulated signals to the waveformreshaping means of the second group, in cases where an electric powergain value of the transmission signal is changed, to select the waveformreshaping means of the second group; a step of generating a new gainsignal of which a new electric power gain value is changed from anelectric power gain value of the gain signal; a step of sending the newgain signal to the multiplying means corresponding to the waveformreshaping means of the second group; and a step of successively sendingthe gain signal having the electric power gain value to the multiplyingmeans corresponding to the waveform reshaping means of the first groupduring a prescribed time period after the change of the gain signal tothe new gain signal.
 14. A signal processing method of a multiplexcommunication according to claim 13, wherein the gain signal having theelectric power gain value is successively sent to the multiplying meanscorresponding to the waveform reshaping means of the first group in thestep of generating the changeover signal and the gain signal until atransient response of the waveform reshaping means of the first group iscompleted.
 15. A signal processing method of a multiplex communicationaccording to claim 13, wherein the changeover signal indicating thechangeover of the waveform reshaping means is periodically generated bythe signal generating means in the step of generating the changeoversignal and the gain signal.
 16. A signal processing method of amultiplex communication according to claim 13, wherein the changeoversignal indicating the changeover of the waveform reshaping means is sentout to select the waveform reshaping means of the second group in thestep of generating the changeover signal and the gain signal in responseto the reception of an instruction which indicates the change of theelectric power gain value of the transmission signal.
 17. A signalprocessing method of a multiplex communication according to claim 13,wherein the information signals sent in a plurality of transmissionchannels are modulated in the step of producing the modulated signals.18. A signal processing method of a multiplex communication according toclaim 13, wherein the electric power controlled signals of the first andsecond groups are added together, in the step of producing the compositemodulation signal, to produce the composite modulation signalcorresponding to the transmission signal which is transmitted from amobile station to a base station.
 19. A signal processing method of amultiplex communication according to claim 13, wherein a spreadingmodulation is performed for the information signals sent in thetransmission channel according to codes in the step of producing themodulated signals to produce a plurality of modulated signals for CDMAcommunication.
 20. A signal processing method of a multiplexcommunication according to claim 18, wherein the composite modulationsignal corresponding to the transmission signal, which is transmittedfrom a mobile station to a base station corresponding to the CDMAcommunication, is produced in the step of producing the compositemodulation signal.